Vega lite KPI Card with target line and conditional text

Question

How can I create a Vega lite KPI Card with target line, conditional text and gradient area chart showing trend?

Answer 1

Try this spec and adjust as needed.

{
  "$schema": "https://vega.github.io/schema/vega-lite/v5.json",
  "usermeta": {"embedOptions": {"renderer": "svg"}},
  "title": {
    "text": "Sales YTD",
    "anchor": "start",
    "offset": -17,
    "font": "Arial",
    "fontSize": 16,
    "fontWeight": 400,
    "color": "#a0a0a0"
  },
  "data": {
    "values": [
      {"date": "2023-01-01", "value": 6000, "target": 10000},
      {"date": "2023-02-01", "value": 8000, "target": 10000},
      {"date": "2023-03-01", "value": 9000, "target": 10000},
      {"date": "2023-04-01", "value": 10000, "target": 12000},
      {"date": "2023-05-01", "value": 8000, "target": 12000},
      {"date": "2023-06-01", "value": 14000, "target": 12000},
      {"date": "2023-07-01", "value": 6000, "target": 14000},
      {"date": "2023-08-01", "value": 15000, "target": 14000},
      {"date": "2023-09-01", "value": 18000, "target": 14000},
      {"date": "2023-10-01", "value": 12000, "target": 16000},
      {"date": "2023-11-01", "value": 12000, "target": 16000},
      {"date": "2023-12-01", "value": 14000, "target": 16000}
    ]
  },
  "height": 100,
  "width": 250,
  "layer": [
    {
      "mark": {
        "type": "area",
        "color": {
          "x1": 1,
          "y1": 1,
          "x2": 1,
          "y2": 0,
          "gradient": "linear",
          "stops": [
            {"offset": 0, "color": "white"},
            {"offset": 1, "color": "#ebebeb"}
          ]
        }
      },
      "encoding": {
        "x": {"field": "date", "type": "temporal", "axis": null},
        "y": {"field": "value", "type": "quantitative", "axis": null}
      }
    },
    {
      "mark": {
        "type": "line",
        "color": "#9c9c9c",
        "strokeWidth": 1,
        "strokeDash": [3, 3]
      },
      "encoding": {
        "x": {"field": "date", "type": "temporal", "axis": null},
        "y": {"field": "target", "type": "quantitative", "axis": null}
      }
    },
    {
      "mark": {"type": "line", "size": 1, "tooltip": true},
      "encoding": {
        "color": {"value": "#000"},
        "x": {"field": "date", "type": "temporal"},
        "y": {"field": "value", "type": "quantitative"}
      }
    },
    {
      "transform": [
        {
          "joinaggregate": [{"op": "max", "field": "date", "as": "latest_date"}]
        },
        {"filter": "datum.date == datum.latest_date"}
      ],
      "mark": {
        "type": "point",
        "tooltip": true,
        "fill": "white",
        "strokeWidth": 1
      },
      "encoding": {
        "color": {
          "condition": {
            "test": "datum.value >= datum.target",
            "value": "green"
          },
          "value": "red"
        },
        "opacity": {"value": 1},
        "size": {"value": 70},
        "x": {"field": "date", "type": "temporal"},
        "y": {"field": "value", "type": "quantitative"}
      }
    },
    {
      "transform": [
        {"joinaggregate": [{"op": "max", "field": "value", "as": "maxVal"}]},
        {
          "joinaggregate": [{"op": "max", "field": "date", "as": "latest_date"}]
        },
        {"filter": "datum.date == datum.latest_date"},
        {
          "calculate": "timeFormat(datum.date,'%b-%Y') + ': '+ format(datum.value,'$,.2s')",
          "as": "Title"
        }
      ],
      "mark": {
        "type": "text",
        "dx": 0,
        "dy": -45,
        "xOffset": 0,
        "yOffset": -10,
        "angle": 0,
        "align": "right",
        "baseline": "bottom",
        "font": "sans-serif",
        "fontSize": 18,
        "fontStyle": "normal",
        "fontWeight": "normal",
        "limit": 0
      },
      "encoding": {
        "x": {"field": "date", "type": "temporal"},
        "y": {"field": "maxVal", "type": "quantitative"},
        "text": {"field": "Title"}
      }
    },
    {
      "transform": [
        {"joinaggregate": [{"op": "max", "field": "value", "as": "maxVal"}]},
        {
          "joinaggregate": [{"op": "max", "field": "date", "as": "latest_date"}]
        },
        {"filter": "datum.date == datum.latest_date"},
        {
          "calculate": "'⚋ Target: '+ format(datum.target,'$,.2s')",
          "as": "targetText"
        }
      ],
      "mark": {
        "type": "text",
        "dx": 0,
        "dy": -25,
        "xOffset": 0,
        "yOffset": -10,
        "angle": 0,
        "align": "right",
        "baseline": "bottom",
        "font": "sans-serif",
        "fontSize": 12,
        "fontStyle": "normal",
        "fontWeight": "normal",
        "limit": 0,
        "color": {"expr": "datum.value < datum.target ? 'red' : 'green'"}
      },
      "encoding": {
        "x": {"field": "date", "type": "temporal"},
        "y": {"field": "maxVal", "type": "quantitative"},
        "text": {"field": "targetText"}
      }
    },
    {
      "transform": [
        {"joinaggregate": [{"op": "max", "field": "value", "as": "maxVal"}]},
        {"calculate": "toDate(datum.date)", "as": "parsed_date"},
        {
          "window": [{"op": "rank", "as": "rank"}],
          "sort": [{"field": "parsed_date", "order": "descending"}]
        },
        {"filter": "datum.rank == 1 || datum.rank == 2"},
        {"calculate": "datum.rank == 1 ? datum.value : 0", "as": "val1"},
        {"calculate": "datum.rank == 2 ? datum.value : 0", "as": "val2"},
        {"joinaggregate": [{"op": "max", "field": "val1", "as": "val1X"}]},
        {"joinaggregate": [{"op": "max", "field": "val2", "as": "val2X"}]},
        {"calculate": "max(datum.val1X) - max(datum.val2X)", "as": "finalVal"},
        {
          "calculate": "datum.rank == 1 ? (datum.finalVal > 0 ? '▲ ' : datum.finalVal < 0 ? '▼ ' : '▷ ') + 'Change this month: ' + (datum.finalVal > 0 ? '+' : '') + format(datum.finalVal,'$,.2s') : ''",
          "as": "subTitle"
        }
      ],
      "mark": {
        "type": "text",
        "dx": 0,
        "dy": -15,
        "xOffset": 0,
        "yOffset": -15,
        "angle": 0,
        "align": "right",
        "baseline": "top",
        "font": "sans-serif",
        "fontSize": 12,
        "fontStyle": "normal",
        "fontWeight": "normal",
        "limit": 0,
        "color": {
          "expr": "datum.finalVal < 0 ? 'red' : datum.finalVal > 0 ? 'green' : 'gray'"
        }
      },
      "encoding": {
        "x": {"field": "date", "type": "temporal"},
        "y": {"field": "maxVal", "type": "quantitative"},
        "text": {"field": "subTitle"}
      }
    }
  ],
  "view": {"stroke": "transparent"},
  "config": {}
}